1. Field of the Invention
The present invention relates to an insertion device which is used to introduce an insertion portion of an endoscope into the body cavity to perform intracavital endoscopy, colonoscopy in particular.
2. Description of the Related Art
In recent years, an endoscope which has a flexible and slender insertion portion has been used in medical fields such as examinations or treatment. Introducing the insertion portion of the endoscope into the body cavity allows observing intracavital organs and the like without cutting, and moreover various types of remedy and treatment can be performed if necessary, by introducing treatment equipment into the body cavity through an treatment equipment insertion channel provided to the insertion portion. The endoscope has a bending portion at the tip portion of the insertion portion. The bending portion is bent in a direction either horizontal or vertical by reciprocal movement of the operation wire which is coupled with a bending piece configuring the bending portion. The operation wire can be moved back and forth by a turning operation of a bending knob provided to the operation part, for example.
With endoscopy, it is necessary to insert the insertion portion into complex body cavity portions. To insert the insertion portion into a complex lumen such as the large intestine with a 360° loop for example, an operator introduces the tip of the insertion portion toward the observation target by operating the bending knob to bend the bending portion while performing a manual operation such as a twisting operation of the insertion portion.
However, considerable skill is required to introduce the insertion portion into the deep region of the complex large intestine smoothly in a short period of time without infliction of discomfort on the patient. In other words, an inexperienced operator may delay the insertion by misdirecting the insertion portion in the deep region or may deform the course of intestines when inserting the insertion portion through to the deep region. Therefore various types proposals have been made to improve the insertability of the insertion portion.
For example, Japanese Unexamined Patent Application Publication No. 10-113396 describes a medical appliance propelling device which can guide a medical appliance up to a deep region of an organism canal easily and less invasively. This propelling device has ribs on a rotary member, the ribs being arranged obliquely as to the axial direction of the rotary member. Therefore the medical appliance coupled with the propelling device is moved toward the deep region by the propulsion force generated from the rotating movement of the rotary member because the rib converts the rotation force of the rotational member into the propulsion force.